Sexually transmitted diseases (STDs) rank among the most common communicable diseases in the world. Despite organized attempts to educate the public, STDs--such as nonspecific urethritis, chlamydial infections, genital and anorectal herpes and warts, syphilis, gonorrhea, chancroid, and granuloma inguinale--continue to represent a significant public health problem. For gonorrhea, it is estimated that greater than 250 million persons worldwide, and close to 3 million in the United States, are infected annually. For syphilis, annual worldwide incidence is estimated at 50 million persons, with 400,000 in the United States annually needing treatment. Other infections, including salmonellosis, shigellosis, campylobacter, hepatitis A, B and C, and cytomegalovirus infection, sometimes are sexually transmitted. Strong associations between cervical cancer and herpes viruses and papillomaviruses have been discovered. More recently, the spread of human immunodeficiency virus (HIV) resulting in fatal acquired immunodeficiency syndrome (AIDS) has spread rapidly in homosexual and heterosexual groups.
STD incidence has risen despite advances in the diagnosis and treatment of these diseases. Factors that have contributed to this trend include changes in sexual behavior, e.g., widespread used of contraceptive pills and devices; more varied sexual practices, including orogenital and anorectal contact; emergence of strains of organisms less sensitive to antibiotics; symptomless carriers of infecting agents; a highly mobile population; a high level of sexual activity involving multiple partners; ignorance of the facts by physicians and the public; and reticence of patients in seeking treatment.
Conventional treatment of STDs has generally been limited to the administration of antibiotic, antifungal or antiviral drugs, such as tetracycline, penicillin, metronidazole, nystatin, miconazole, sulphamethoxazole and acyclovir, after the transmission and diagnosis of the STD has been made. Conventional prophylaxis for STDs has generally been limited to the use of physical barriers, such as condoms, that prevent or diminish the exchange of bodily fluids during sexual intercourse. Although certain advances have been made in the diagnosis and treatment of STDs, a strong need exists for new methods and compositions that prevent infection by pathogenic microbes during and immediately following sexual activity. Even in the case of curable STDs, prevention is highly preferable to symptomic diagnosis and treatment.